CLN: Minor cleanup of caching

pandas/core/base.py

@@ -80,6 +80,7 @@ class PandasObject(DirNamesMixin):
     Baseclass for various pandas objects.
     """
 
+    # results from calls to methods decorated with cache_readonly get added to _cache
     _cache: Dict[str, Any]
 
     @property
@@ -100,14 +101,14 @@ def _reset_cache(self, key: Optional[str] = None) -> None:
         """
         Reset cached properties. If ``key`` is passed, only clears that key.
         """
-        if getattr(self, "_cache", None) is None:
+        if not hasattr(self, "_cache"):
             return
         if key is None:
             self._cache.clear()
         else:
             self._cache.pop(key, None)
 
-    def __sizeof__(self):
+    def __sizeof__(self) -> int:
         """
         Generates the total memory usage for an object that returns
         either a value or Series of values

pandas/core/indexes/range.py

@@ -238,7 +238,7 @@ def _format_with_header(self, header: List[str], na_rep: str = "NaN") -> List[st
         "instead"
     )
 
-    @cache_readonly
+    @property
     def start(self):
         """
         The value of the `start` parameter (``0`` if this was not supplied).
@@ -261,7 +261,7 @@ def _start(self):
         )
         return self.start
 
-    @cache_readonly
+    @property
     def stop(self):
         """
         The value of the `stop` parameter.
@@ -284,7 +284,7 @@ def _stop(self):
         )
         return self.stop
 
-    @cache_readonly
+    @property
     def step(self):
         """
         The value of the `step` parameter (``1`` if this was not supplied).

pandas/tests/indexes/ranges/test_range.py

@@ -203,7 +203,7 @@ def test_cache(self):
         idx._data
         assert isinstance(idx._data, np.ndarray)
         assert idx._data is idx._data  # check cached value is reused
-        assert len(idx._cache) == 4
+        assert len(idx._cache) == 1
         expected = np.arange(0, 100, 10, dtype="int64")
         tm.assert_numpy_array_equal(idx._cache["_data"], expected)